[Relationship between clinical stages of nasopharyngeal carcinoma and Epstein-Barr virus antibodies Rta/IgG, EBNA1/IgA, VCA/IgA and EA/IgA].

OBJECTIVE: To evaluate the relationship between the clinical stages of nasopharyngeal carcinoma (NPC) and Epstein-Barr virus (EBV) antibodies Rta/IgG, EBNA1/IgA, VCA/IgA and EA/IgA. METHODS: Serum samples obtained from 211 untreated patients with NPC categorized by the project of 92' stage were examined for the presence of the EBV antibodies Rta/IgG and EBNA1/IgA by enzyme-linked immnunosorbent assay (ELISA) and for VCA/IgA and EA/IgA by immunoenzymatic assay. The positive rates and antibody levels in the NPC patients in different TNM stages and clinical stages were analyzed statistically. RESULTS: No significant difference in Rta/IgG rA value was found in the NPC patients in different TNM or clinical stages (P>0.05). The EBNA1/IgA rA value was significantly lower in stage T1, N0, and clinical stage I than in the other corresponding T stages, N stages and other clinical stage (P<0.05). The antibody titers of VCA/IgA and EA/IgA differed significantly between the N stages and the clinical stages (P<0.05). CONCLUSION: The expression of EBV Rta/IgG is not associated with NPC stage. The expression of EBNA1/IgA is relatively low in early NPC. The antibody level of VCA/IgA and EA/IgA are significantly correlated to the degree of neck lymph node metastasis, and might be helpful to classify the clinical stages of NPC.

[Evaluation of detection of Epstein-Barr virus Rta/IgG in nasopharyngeal carcinoma].

OBJECTIVE: This study was aimed to investigate the clinical value of Epstein-Barr virus (EBV) Rta/IgG in the diagnosis of nasopharyngeal carcinoma (NPC). METHODS: Serum samples derived from 211 untreated patients with NPC, 413 subjects including 203 non-NPC ENT patients and 210 healthy volunteers as control were examined for the presence of antibodies directed against Rta/IgG by using enzyme-linked immnunosorbent assay (ELISA). Receiver operating characteristic (ROC) curve was applied to perform methodical evaluation of this tumor marker. RESULTS: The rA value median of Rta/IgG in NPC group was significantly higher than one in control group (P < 0.001). The area under ROC was 0.933. The sensitivity and specificity of this marker were 90.5% and 90.1%, respectively, when the best cutoff value was defined. CONCLUSION: Rta/IgG detected with ELISA method is a new target of EBV, and may be one of important marker for NPC diagnosis.

[Evaluation of combined determinations of Epstein-Barr virus antibodies for nasopharyngeal carcinoma assessed with receiver operating characteristic curve based on logistic regression].

OBJECTIVE: This study was aimed to investigate the diagnostic value of combined determination of Epstein-Barr virus (EBV) antibodies for nasopharyngeal carcinoma (NPC), including immunoglobulin (Ig) A against EBV capsid antigens (VCA), IgA against early antigens (EA), IgG against BRLF1 transcription activator (Rta) and IgA against EBV nuclear antigen-1 (EBNA1), assessed with receiver operating characteristic (ROC) curve based on logistic regression. METHODS: Serum samples derived from 211 untreated patients with NPC and 203 non-NPC ENT patients were examined for the presence of VCA/IgA and EA/IgA by immunoenzymatic assay, Rta/IgG and EBNA1/IgA by enzyme-linked immnunosorbent assay (ELISA). The different Logistic regression models were established for various combined determinations of antibodies, respectively. Using the predicted probability as the analyzed variable, ROC curve was applied to evaluate the diagnostic accuracy of different combined determinations. RESULTS: The sensitivity of VCA/IgA (98.1%) and the specificity of EA/IgA (98.5%) were the highest while detecting solely. The results which were analyzed by ROC curve based on Logistic regression showed that the sensitivity and specificity were improved. In two-marker combinations, VCA/IgA + Rta/IgG whose area under ROC curve (AUC) was 0.991 had the highest diagnostic accuracy, and its sensitivity, specificity and Youden index were 94.8%, 98.0% and 0.928 respectively. No significant difference of AUC were found comparing VCA/IgA + Rta/IgG with VCA/IgA + Rta/IgG + EBNA1/IgA and four-marker combination( P > 0.05), of which sensitivity, specificity and Youden index were 94.8%, 98.5%, 0.933 and 96.7%, 97.0%, 0.937, respectively. CONCLUSION: The approach of ROC curve based on Logistic regression can improve synthetic efficiency for combined determination of multiple markers. The combined determination of VCA/IgA and Rta/IgG with a complementary effect is optimal for NPC serodiagnosis.